Long-acting heavy-duty special coating for industrial equipment and preparation method thereof
By constructing a triple protection system of physical shielding, chemical passivation, and interface anchoring, the problem of insufficient corrosion resistance and durability of existing industrial coatings under harsh working conditions is solved, achieving long-term protection of industrial metal substrates and improving the heat resistance and interface adhesion of the coating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PAINT MFG CO SHENZHEN
- Filing Date
- 2026-03-25
- Publication Date
- 2026-06-12
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coating technology, specifically relating to a long-lasting, heavy-duty anti-corrosion coating for industrial equipment and its preparation method. Background Technology
[0002] Industrial coatings, as indispensable protective materials in equipment manufacturing, infrastructure, chemical equipment, and marine engineering, directly determine the service life and operational safety of metal components. In modern industrial systems, industrial coatings have evolved from traditional decorative coatings into functional materials integrating corrosion resistance, temperature resistance, media resistance, and aging resistance. Mainstream systems include epoxy resin coatings, polyurethane coatings, acrylic coatings, fluorocarbon coatings, and inorganic zinc-rich coatings. These coatings rely on the physical shielding effect of the film-forming resin and the passivation and corrosion inhibition effects of the rust-inhibiting pigments to protect the metal substrate. They are widely used in critical equipment such as storage tanks, pipelines, reactors, steel structures, and offshore platforms, and are a core technological means for corrosion prevention and extending the service life of industrial equipment.
[0003] Although existing industrial coatings have achieved large-scale application, performance bottlenecks remain insurmountable under harsh operating conditions, failing to meet the demands for long-term, heavy-duty corrosion protection. Insufficient corrosion resistance and durability are common issues; ordinary industrial coatings are prone to chalking, cracking, and blistering in strong acid, alkali, and humid environments. Once the protective layer fails, corrosive media rapidly penetrate the substrate, leading to equipment rust and requiring recoating within a short period, increasing costs and downtime risks. Poor environmental and media resistance is also a concern. Chemical equipment frequently comes into contact with oils, solvents, and acidic / alkaline liquids, causing conventional coatings to swell and dissolve, resulting in decreased adhesion and peeling. Under alternating high and low temperature conditions, the mismatch in thermal expansion coefficients between the resin and the substrate can easily lead to internal stress cracking, causing the protective system to fail. Water-based coatings require stringent curing conditions; poor film formation and long drying cycles at low temperatures and high humidity affect application efficiency. Insufficient wettability and adhesion to older equipment and complex substrates can also lead to defects such as missed areas and pinholes.
[0004] In response to the urgent need for long-term protection of high-end industrial equipment, existing industrial coatings still have shortcomings in terms of corrosion protection life, environmental resistance, and mechanical properties. Therefore, it is necessary to develop long-lasting heavy-duty anti-corrosion coatings for industrial equipment to provide reliable protection for the safe and stable operation of industrial equipment under harsh working conditions and promote the development of heavy-duty anti-corrosion coatings towards high performance, greenness, and specialization. Summary of the Invention
[0005] To address the shortcomings of existing industrial coatings in terms of corrosion resistance, environmental tolerance, and mechanical properties, this invention provides a long-lasting, heavy-duty anti-corrosion coating for industrial equipment and its preparation method. The method involves preparing a siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, a composite passivator, and a modified polyamide-ketoimine-epoxy composite, which are then combined with other functional components. Through the synergistic design of the substrate, passivation, and curing systems, a triple protection system of physical shielding, chemical passivation, and interface anchoring is constructed, achieving long-lasting protection for industrial metal substrates. The specific technical solution is as follows:
[0006] A long-lasting, heavy-duty anti-corrosion coating for industrial equipment is prepared by mixing a base component and a curing agent component at a mass ratio of 100:26-28, and adjusting the pressure to 3000-5000 mPa·s with 1,4-butanediol diglycidyl ether. The base component is made from the following raw materials in parts by mass: 45-50 parts of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, 10-15 parts of composite passivating agent, 6-8 parts of hydrophobic silica, 9-13 parts of barium sulfate, 3-6 parts of 1,4-butanediol diglycidyl ether, 0.3-0.6 parts of wetting agent, 0.2-0.4 parts of defoamer, 0.4-0.8 parts of dispersant, and 0.3-0.7 parts of anti-settling agent. The curing agent component is a modified polyamide-ketoimine-epoxy composite.
[0007] In the above coating, the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin is prepared by stirring bisphenol F epoxy resin and methyl naphthol aldehyde resin in propylene glycol methyl ether acetate, adding premixed γ-aminopropyltriethoxysilane and reacting with triphenylphosphine at 85-90°C, and then adding hydroxyethyl phosphate, diethanolamine and hydroquinone and reacting at 75-80°C. The composite passivating agent is prepared by stirring and dispersing aluminum borate, sericite powder, deionized water, and sodium polyacrylate, adding cerium nitrate at 60-65℃ and dispersing, adjusting the pH to 8.5-9.0, adding aniline at 2-6℃ and stirring, then adding diluted ammonium persulfate in hydrochloric acid solution to react, followed by pressure filtration, washing, drying, pre-oxidation at 380-420℃, calcination at 450-500℃, and pulverization. The modified polyamide-ketoimine-epoxy composite is prepared by reacting a dimer acid with triethylenetetramine at 120–125°C, dehydrating it at 200–220°C, adding methyl isobutyl ketone for reflux dehydration at 110–120°C, adding bisphenol F epoxy resin and benzoic acid at 70–80°C, and reacting at 90–95°C.
[0008] In the above coating, the wetting agent is BYK-333 or TEGO Wet 270; the defoamer is BYK-065 or TEGO Foamex N; the dispersant is EFKA-6220 or Solsperse 20000; and the anti-settling agent is KMT-4006.
[0009] Furthermore, the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin is prepared by mixing bisphenol F epoxy resin, methyl naphthol aldehyde resin, propylene glycol methyl ether acetate, γ-aminopropyltriethoxysilane, triphenylphosphine, hydroxyethyl phosphate, diethanolamine, and hydroquinone in a mass ratio of (60-70):(30-40):(25-30):(8-10):(0.1-0.15):(4-6):(2.5-3.5):(0.05-0.08). The bisphenol F epoxy resin and methyl naphthol aldehyde resin are stirred in propylene glycol methyl ether acetate at 70-75°C. Premixed γ-aminopropyltriethoxysilane and triphenylphosphine are added and reacted at 85-90°C. Hydroxyethyl phosphate, diethanolamine, and hydroquinone are added and reacted at 75-80°C.
[0010] Furthermore, the preparation method of the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin includes the following steps: 60-70 parts by weight of bisphenol F epoxy resin, 30-40 parts by weight of methyl naphthol aldehyde resin, and 25-30 parts by weight of propylene glycol methyl ether acetate are stirred at 70-75°C for 30-50 min to obtain a resin mixture; 8-10 parts by weight of γ-aminopropyltriethoxysilane and 0.1-0.15 parts by weight of triphenylphosphine are premixed and added dropwise to the resin mixture; the mixture is stirred at 85-90°C for 3-4 h; 4-6 parts by weight of hydroxyethyl phosphate, 2.5-3.5 parts by weight of diethanolamine, and 0.05-0.08 parts by weight of hydroquinone are added at 75-80°C; the mixture is stirred for 3-4 h; and the mixture is filtered to obtain the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin.
[0011] Furthermore, the composite passivating agent is composed of aluminum borate, sericite powder, deionized water, sodium polyacrylate, cerium nitrate, aniline, 1.0–1.2 mol / L hydrochloric acid aqueous solution, and ammonium persulfate in a mass ratio of (50–60):(40–50):(120–150):(0.8–1.2):(4–6):(8–12):(120–130):(20–30). Water and sodium polyacrylate are stirred and dispersed. Cerium nitrate is added at 60-65℃ and the pH is adjusted to 8.5-9.0. Aniline is added and stirred while maintaining the temperature at 2-6℃. Ammonium persulfate diluted with 1.0-1.2 mol / L hydrochloric acid aqueous solution is added dropwise and stirred for 6-8 hours. After pressure filtration, washing, and drying, the mixture is pre-oxidized at 380-420℃ in air and calcined at 450-500℃ in nitrogen atmosphere for 1.5-2 hours. Finally, the mixture is pulverized to obtain the final product.
[0012] Further, the preparation method of the composite passivating agent includes the following steps: 50-60 parts by weight of aluminum borate, 40-50 parts by weight of sericite powder, 120-150 parts by weight of deionized water, and 0.8-1.2 parts by weight of sodium polyacrylate are stirred and dispersed to obtain a suspension; 4-6 parts by weight of cerium nitrate are added at 60-65°C, stirred and dispersed, the pH value is adjusted to 8.5-9.0, and at a temperature of 2-6°C, 8-12 parts by weight of aniline are added and stirred; 20-30 parts by weight of ammonium persulfate diluted with 120-130 parts by weight of 1.0-1.2 mol / L hydrochloric acid aqueous solution are added dropwise, stirred for 6-8 hours, filtered under pressure, the filter cake is washed with deionized water until the conductivity of the washing liquid is below 50 μS / cm, vacuum dried, pre-oxidized at 380-420°C in air for 1-1.5 hours, calcined at 450-500°C in nitrogen for 1.5-2 hours, and pulverized to a median particle size of below 3 μm to obtain the composite passivating agent.
[0013] Furthermore, the modified polyamide-ketoimine-epoxy composite is prepared by reacting dimer acid, triethylenetetramine, methyl isobutyl ketone, bisphenol F epoxy resin, and benzoic acid in a mass ratio of (100-120):(32-36):(18-22):(15-20):(0.2-0.3). The dimer acid is first reacted with triethylenetetramine at 120-125°C for 1-1.5 h, then dehydrated at 200-220°C for 4-5 h, then methyl isobutyl ketone is added at 110-120°C and refluxed for 3-4 h, and finally bisphenol F epoxy resin and benzoic acid are added at 70-80°C and reacted at 90-95°C for 2-2.5 h.
[0014] Furthermore, the preparation method of the modified polyamide-ketoimine-epoxy composite includes the following steps: 100-120 parts by weight of dimer acid and 32-36 parts by weight of triethylenetetramine are stirred and reacted at 120-125°C for 1-1.5 hours; dehydrated at 200-220°C using a water separator for 4-5 hours; 18-22 parts by weight of methyl isobutyl ketone are added at 110-120°C and refluxed for 3-4 hours; 15-20 parts by weight of bisphenol F epoxy resin and 0.2-0.3 parts by weight of benzoic acid are added at 70-80°C; the mixture is reacted at 90-95°C for 2-2.5 hours; and filtered to obtain the modified polyamide-ketoimine-epoxy composite.
[0015] The preparation method of the above-mentioned long-lasting heavy-duty anti-corrosion coating for industrial equipment is characterized by the following steps: according to the formula, siloxane-phosphorus nitrogen modified bisphenol F-naphthol aldehyde hybrid resin and 1,4-butanediol diglycidyl ether are stirred, and wetting agent, defoamer and dispersant are added in sequence and stirred; composite passivating agent, hydrophobic silica and barium sulfate are added and dispersed below 30°C, and ground to a fineness of less than 20μm below 40°C; anti-settling agent is added and stirred, filtered, and the base material component is obtained; when using, the base material component and curing agent component are mixed according to the formula ratio, adjusted to 3000-5000 mPa·s with 1,4-butanediol diglycidyl ether, and allowed to stand to obtain the coating.
[0016] This invention provides a long-lasting, heavy-duty anti-corrosion coating for industrial equipment and its preparation method, with the following beneficial effects: I. The long-lasting heavy-duty anti-corrosion coating for industrial equipment of this invention constructs a triple protection system of physical shielding, chemical passivation, and interface anchoring through the synergistic design of three major systems: substrate, passivation, and curing. This solves the problems of insufficient anti-corrosion durability and poor environmental and media resistance of traditional industrial coatings, and achieves long-lasting protection for industrial metal substrates.
[0017] II. In the preparation of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, the compounding of bisphenol F epoxy resin and methyl naphthol aldehyde resin utilizes the high crosslinking activity of bisphenol F to improve the adhesion to the substrate, while the rigid naphthalene ring of the naphthol aldehyde resin enhances the crosslinking density, heat resistance, and media barrier properties of the coating, providing a basic framework for the resin. The addition of γ-aminopropyltriethoxysilane and triphenylphosphine for siloxane grafting introduces high-bond-energy Si-O-Si bonds. This reduces the surface energy of the coating, achieving hydrophobic protection, and allows the Si-O bonds to form chemical bonds with the metal substrate, upgrading the interfacial bonding from physical adsorption to chemical anchoring, thus strengthening the interfacial adhesion. Simultaneously, the Si-O-Si bonds improve the coating's resistance to heat and oxygen aging and UV degradation, match the thermal expansion coefficient of the substrate, and reduce internal stress under high and low temperature alternating stresses. The addition of hydroxyethyl phosphate, diethanolamine, and hydroquinone as a polymerization inhibitor enables phosphorus and nitrogen functionalization, forming a dense phosphate passivation film on the metal surface to achieve chemical corrosion inhibition. Simultaneously, it increases resin crosslinking points, improves the density of the shielding layer, and blocks the penetration of corrosive media. Precise addition of hydroquinone prevents high-temperature oxidative degradation of the resin, ensuring the uniformity of the resin structure. Accurate control of the mass ratio and parameters of each raw material ensures the complete reaction of siloxane grafting and phosphorus and nitrogen functionalization, avoiding coating defects caused by unreacted functional groups, thus achieving the triple functions of resin interface anchoring, chemical corrosion inhibition, and dense shielding.
[0018] III. In the preparation of the composite passivating agent, the lamellar structure of aluminum borate and sericite powder forms a labyrinthine physical barrier in the coating, extending the penetration path of corrosive media. Rare earth ions in cerium nitrate form a stable cerium-based oxide passivation film on the metal surface, inhibiting the cathodic oxygen reduction reaction and achieving rare earth passivation. Polyaniline possesses redox reversibility, which helps in the self-repair of local defects in the coating. Rare earth ion adsorption ensures uniform loading of cerium nitrate on the lamellar filler, aniline polymerization avoids high-temperature agglomeration of polyaniline, and pre-oxidation and calcination enable polyaniline to form a dense conjugated structure, activating the lamellar structure of aluminum borate and sericite powder and enhancing the physical shielding effect. Compared with simple mixtures, the composite passivating agent has good dispersibility, avoiding the formation of interface defects in the coating.
[0019] IV. In the preparation of the modified polyamide-ketoimine-epoxy composite curing agent, the synthesis of polyamide from dimer acid and triethylenetetramine introduces flexible segments, reducing the internal stress of the cured coating and improving its impact resistance and flexibility. Dehydration and ketoimine end-capping end-capping impart moisture-curing and low-temperature curing properties to the curing agent. Ketoimine hydrolyzes upon contact with water to regenerate primary amines, preferentially consuming interfacial water molecules, reducing the risk of coating blistering, and adapting to wide temperature range construction conditions of low temperature and high humidity. The epoxy composite reaction with bisphenol F epoxy resin and benzoic acid catalyst improves the compatibility between the curing agent and the self-developed resin, forming an interpenetrating cross-linked network, avoiding microphase separation, and improving the coating's resistance to media and structural stability. The control of various parameters ensures the structural integrity of the curing agent, achieving flexible cross-linking, moisture curing, and high compatibility, forming a uniform cross-linked network with the self-developed resin.
[0020] V. In the preparation of the coating mixture, the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin is first mixed with an active diluent. Then, wetting, defoaming, and dispersing agents are added sequentially. Finally, a composite passivating agent, hydrophobic silica, and barium sulfate are added to prevent the agglomeration of functional fillers and ensure the dispersion and wetting effect of the additives on the fillers. 1,4-Butanediol diglycidyl ether not only adjusts the application viscosity but also participates in the resin crosslinking reaction, avoiding the decrease in coating crosslinking density caused by inactive diluents and ensuring coating performance.
[0021] In summary, the epoxy functional groups of the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin are precisely matched with the amine and ketimine groups of the modified curing agent, forming a highly cross-linked interpenetrating network. The flexible segments of the curing agent compensate for the rigidity of the resin, and the chemical anchoring of the resin and the wet curing characteristics of the curing agent synergistically enhance the interfacial bonding force, preventing internal stress cracking under high and low temperature alternation. The chemical passivation film formed by the phosphorus nitrogen functionalization of the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, together with the rare earth passivation film of the composite passivator and the self-healing properties of polyaniline, forms a multi-layered dense passivation system on the metal surface. The hydrophobic shielding layer of the resin and the labyrinthine physical barrier of the passivator synergistically block the penetration of corrosive media, achieving dual protection of chemical corrosion inhibition and physical shielding. Hydrophobic silica enhances the hardness and hydrophobicity of the resin coating, while barium sulfate, as an inert filler, enhances the density and mechanical strength of the coating. Both, together with the dense cross-linked network of the resin, further enhance the physical shielding performance of the coating without affecting the interfacial bonding between the resin and the substrate. Interface anchoring ensures the bonding stability between the coating and the substrate, chemical passivation enables active corrosion inhibition on the metal surface, and physical shielding blocks the penetration path of corrosive media, ultimately achieving long-lasting heavy-duty anti-corrosion performance of the coating. Detailed Implementation
[0022] Some embodiments are given below, but the present invention is not limited to these embodiments.
[0023] Example 1 A long-lasting, heavy-duty anti-corrosion coating for industrial equipment is prepared by mixing a base component and a curing agent component at a mass ratio of 100:27, and adjusting the pressure to 4000 mPa·s with 1,4-butanediol diglycidyl ether. The base component is made from the following raw materials in parts by mass: 47 parts of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, 12 parts of composite passivating agent, 7 parts of hydrophobic silica, 11 parts of barium sulfate, 5 parts of 1,4-butanediol diglycidyl ether, 0.5 parts of wetting agent, 0.3 parts of defoamer, 0.55 parts of dispersant, and 0.5 parts of anti-settling agent. The curing agent component is a modified polyamide-ketoimine-epoxy composite. Specifically, the wetting agent is BYK-333; the defoamer is TEGO Foamex N; the dispersant is EFKA-6220; and the anti-settling agent is KMT-4006.
[0024] The preparation method of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin includes the following steps: 65 parts by mass of bisphenol F epoxy resin, 35 parts by mass of methyl naphthol aldehyde resin, and 28 parts by mass of propylene glycol methyl ether acetate are added to a reaction vessel, a reflux condenser is installed, and the mixture is stirred at 70-75℃ and 400 rpm for 40 minutes to obtain a resin mixture; 9 parts by mass of γ-aminopropyltriethoxysilane and 0.12 parts by mass of triphenylphosphine are premixed and then added dropwise. The resin mixture was refluxed at 85–90°C and stirred at 400 rpm for 3.5 h to achieve siloxane grafting. The mixture was then refluxed at 75–80°C, and 5 parts of hydroxyethyl phosphate, 3 parts of diethanolamine, and 0.07 parts of hydroquinone were added sequentially. The mixture was stirred at 400 rpm for 3.5 h to achieve phosphorus and nitrogen functionalization. The mixture was then cooled to below 40°C and filtered through a 100-mesh filter to obtain the siloxane-phosphorus-nitrogen modified bisphenol F-naphthol aldehyde hybrid resin.
[0025] The preparation of the methyl-Naphthol aldehyde resin includes the following steps: The mass ratio of methyl-Naphthol: 37wt% formaldehyde aqueous solution: sodium hydroxide: deionized water = 105:58:3.5:23 is used. The mixture is stirred at 350 rpm for 35 min at a temperature of 40–50℃ until the methyl-Naphthol is completely dissolved. The temperature is then increased to 65–75℃ and stirred at 350 rpm for 2.5 h to carry out the hydroxymethyl addition reaction. The temperature is further increased to 85–90℃ and refluxed at 350 rpm for 1.5 h. Dilute hydrochloric acid is added to adjust the pH of the system to 7.2. Free water in the system is removed under reduced pressure to obtain the methyl-Naphthol aldehyde resin with a molecular weight range of 800–1500.
[0026] The preparation method of the composite passivating agent includes the following steps: 55 parts by mass of aluminum borate, 45 parts by mass of sericite powder, 130 parts by mass of deionized water, and 1 part by mass of sodium polyacrylate are added to a disperser and sheared and dispersed at 1100 rpm for 40 min to obtain a suspension; the suspension is transferred to a jacketed reactor, and 5 parts by mass of cerium nitrate are added at 62℃ and stirred and dispersed at 550 rpm for 40 min; the pH is adjusted to 8.8 with ammonia water to complete the rare earth ion adsorption; the temperature is lowered to 4℃, and 10 parts by mass of aniline are added and stirred. After 35 minutes, 25 parts of ammonium persulfate diluted with 125 parts of 1.1 mol / L hydrochloric acid aqueous solution were added dropwise at a rate of 1 drop / second. After the addition was completed, the mixture was stirred at 550 rpm for 7 hours, with the temperature controlled between 2 and 6 °C throughout the process. The mixture was then filtered under pressure, and the filter cake was repeatedly washed with deionized water until the conductivity of the washing liquid was below 50 μS / cm. The mixture was then vacuum dried at 85 °C for 3.5 hours, pre-oxidized at 400 °C in air for 1 hour, calcined at 480 °C in nitrogen for 1.5 hours, and pulverized to a median particle size of 1.2 μm to obtain the composite passivating agent.
[0027] The preparation method of the modified polyamide-ketoimine-epoxy composite includes the following steps: 110 parts by mass of dimer acid and 34 parts by mass of triethylenetetramine are added to a reaction vessel, a water separation and reflux device is installed, and the reaction is carried out at 120-125℃ and 350 rpm for 1 hour by stirring. The temperature is then increased to 200-220℃, and the mixture is dehydrated by a water separator for 4.5 hours. The temperature is then lowered to 110-120℃, 20 parts by methyl isobutyl ketone are added, and the mixture is refluxed for 3.5 hours to complete the ketoimine end-capping. The temperature is then lowered to 75℃, 18 parts by bisphenol F epoxy resin and 0.25 parts by benzoic acid are added, and the mixture is reacted at 90-95℃ and 350 rpm for 2 hours. The temperature is then lowered to below 40℃, and the mixture is filtered through a 100-mesh filter to obtain the modified polyamide-ketoimine-epoxy composite.
[0028] The preparation method of the above-mentioned long-lasting heavy-duty anti-corrosion coating for industrial equipment includes the following steps: According to the formula, siloxane-phosphorus nitrogen modified bisphenol F-naphthol aldehyde hybrid resin and 1,4-butanediol diglycidyl ether are added to the paint mixing kettle and stirred at 550 rpm. Wetting agent, defoamer and dispersant are added in sequence and stirred for 12 min until uniform. The jacket is cooled and the temperature is controlled below 30℃. The composite passivating agent, hydrophobic silica and barium sulfate are added under stirring at 320 rpm and dispersed at 1800 rpm for 35 min. The mixture is then transferred to a sand mill and ground to a fineness of less than 20 μm under cooling water circulation and temperature control below 40℃. The mixture is then transferred back to the paint mixing kettle, anti-settling agent is added, and the mixture is stirred at 320 rpm for 25 min. The mixture is then filtered through a 100-mesh filter to obtain the base material component. When using, the base material component and curing agent component are mixed according to the formula ratio, and the mixture is adjusted to 4000 mPa·s (25℃) with 1,4-butanediol diglycidyl ether and allowed to stand to obtain the coating.
[0029] Example 2 A long-lasting, heavy-duty anti-corrosion coating for industrial equipment is prepared by mixing a base component and a curing agent component at a mass ratio of 100:26, and adjusting the pressure to 3000 mPa·s with 1,4-butanediol diglycidyl ether. The base component is made from the following raw materials in parts by mass: 45 parts of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, 10 parts of composite passivating agent, 6 parts of hydrophobic silica, 9 parts of barium sulfate, 3 parts of 1,4-butanediol diglycidyl ether, 0.3 parts of wetting agent, 0.2 parts of defoamer, 0.4 parts of dispersant, and 0.3 parts of anti-settling agent. The curing agent component is a modified polyamide-ketoimine-epoxy composite. Specifically, the wetting agent is BYK-333; the defoamer is BYK-065; the dispersant is EFKA-6220; and the anti-settling agent is KMT-4006.
[0030] The preparation method of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin includes the following steps: 60 parts by mass of bisphenol F epoxy resin, 30 parts by mass of methyl naphthol aldehyde resin, and 25 parts by mass of propylene glycol methyl ether acetate are added to a reaction vessel, a reflux condenser is installed, and the mixture is stirred at 70-75℃ and 300 rpm for 30 minutes to obtain a resin mixture; 8 parts by mass of γ-aminopropyltriethoxysilane and 0.1 parts by mass of triphenylphosphine are premixed and then added dropwise. The resin mixture was added and reacted at 85–90°C under reflux with stirring at 300 rpm for 3 hours to achieve siloxane grafting. The mixture was then refluxed at 75–80°C, and 4 parts of hydroxyethyl phosphate, 2.5 parts of diethanolamine, and 0.05 parts of hydroquinone were added sequentially. The mixture was stirred at 300 rpm for 3 hours to achieve phosphorus and nitrogen functionalization. The mixture was then cooled to below 40°C and filtered through a 100-mesh filter to obtain the siloxane-phosphorus and nitrogen modified bisphenol F-naphthol aldehyde hybrid resin.
[0031] The preparation of the methyl-Naphthol aldehyde resin includes the following steps: Naphthol: 37wt% formaldehyde aqueous solution: sodium hydroxide: deionized water = 100:55:3:20 by mass ratio; react at 40–50℃ and 300 rpm for 30 min until the methyl-Naphthol is completely dissolved; heat to 65–75℃ and stir at 300 rpm for 2 h to carry out the hydroxymethyl addition reaction; continue heating to 85–90℃ and reflux at 300 rpm for 1.5 h; add dilute hydrochloric acid to adjust the pH of the system to 7.0; remove free water from the system under reduced pressure to obtain the methyl-Naphthol aldehyde resin with a molecular weight range of 800–1500.
[0032] The preparation method of the composite passivating agent includes the following steps: 50 parts by mass of aluminum borate, 40 parts by mass of sericite powder, 120 parts by mass of deionized water, and 0.8 parts by mass of sodium polyacrylate are added to a disperser and sheared at 1000 rpm for 30 minutes to obtain a suspension; the suspension is transferred to a jacketed reactor, and at 60°C, 4 parts by mass of cerium nitrate are added and stirred at 500 rpm for 30 minutes. The pH is adjusted to 8.5 with ammonia water to complete the rare earth ion adsorption; the temperature is lowered to 2°C, and 8 parts by mass of aniline are added and stirred... After stirring for 30 minutes, 20 parts of ammonium persulfate diluted with 120 parts of 1.0 mol / L hydrochloric acid aqueous solution were added dropwise at a rate of 1 drop / second. After the addition was completed, the mixture was stirred at 500 rpm for 6 hours, with the temperature controlled between 2 and 6℃ throughout the process. The mixture was then filtered under pressure, and the filter cake was repeatedly washed with deionized water until the conductivity of the washing liquid was below 50 μS / cm. The mixture was then vacuum dried at 80℃ for 3 hours, pre-oxidized at 380℃ in air for 1 hour, calcined at 450℃ in nitrogen for 1.5 hours, and pulverized to a median particle size of 2.6 μm to obtain the composite passivating agent.
[0033] The preparation method of the modified polyamide-ketoimine-epoxy composite includes the following steps: 100 parts by mass of dimer acid and 32 parts by mass of triethylenetetramine are added to a reaction vessel, a water separation and reflux device is installed, and the reaction is carried out at 120-125℃ and 300 rpm for 1 hour by stirring. The temperature is then increased to 200-220℃, and the mixture is dehydrated by a water separator for 4 hours. The temperature is then lowered to 110-120℃, 18 parts by methyl isobutyl ketone are added, and the mixture is refluxed for 3 hours to complete the ketoimine end-capping. The temperature is then lowered to 70℃, 15 parts by bisphenol F epoxy resin and 0.2 parts by benzoic acid are added, and the mixture is reacted at 90-95℃ and 300 rpm for 2 hours. The temperature is then lowered to below 40℃, and the mixture is filtered through a 100-mesh filter to obtain the modified polyamide-ketoimine-epoxy composite.
[0034] The preparation method of the above-mentioned long-lasting heavy-duty anti-corrosion coating for industrial equipment includes the following steps: According to the formula, siloxane-phosphorus nitrogen modified bisphenol F-naphthol aldehyde hybrid resin and 1,4-butanediol diglycidyl ether are added to the paint mixing kettle and stirred at 500 rpm. Wetting agent, defoamer and dispersant are added in sequence and stirred for 10 min until uniform. The jacket is cooled and the temperature is controlled below 30℃. The composite passivating agent, hydrophobic silica and barium sulfate are added under stirring at 300 rpm and dispersed at high speed at 1500 rpm for 30 min. The mixture is then transferred to a sand mill and ground to a fineness of less than 20 μm under cooling water circulation and temperature control below 40℃. The mixture is then transferred back to the paint mixing kettle, anti-settling agent is added, and the mixture is stirred at 300 rpm for 20 min. The mixture is then filtered through a 100-mesh filter to obtain the base material component. When using, the base material component and curing agent component are mixed according to the formula ratio, and the mixture is adjusted to 3000 mPa·s (25℃) with 1,4-butanediol diglycidyl ether and allowed to stand to obtain the coating.
[0035] Example 3 A long-lasting, heavy-duty anti-corrosion coating for industrial equipment is prepared by mixing a base component and a curing agent component at a mass ratio of 100:28, and adjusting the pressure to 5000 mPa·s with 1,4-butanediol diglycidyl ether. The base component is made from the following raw materials in parts by mass: 50 parts of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, 15 parts of composite passivating agent, 8 parts of hydrophobic silica, 13 parts of barium sulfate, 6 parts of 1,4-butanediol diglycidyl ether, 0.6 parts of wetting agent, 0.4 parts of defoamer, 0.8 parts of dispersant, and 0.7 parts of anti-settling agent. The curing agent component is a modified polyamide-ketoimine-epoxy composite. Specifically, the wetting agent is TEGO Wet 270; the defoamer is TEGO Foamex N; the dispersant is Solsperse 20000; and the anti-settling agent is KMT-4006.
[0036] The preparation method of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin includes the following steps: 70 parts by mass of bisphenol F epoxy resin, 40 parts by mass of methyl naphthol aldehyde resin, and 30 parts by mass of propylene glycol methyl ether acetate are added to a reaction vessel, a reflux condenser is installed, and the mixture is stirred at 70-75℃ and 500 rpm for 50 minutes to obtain a resin mixture; 10 parts by mass of γ-aminopropyltriethoxysilane and 0.15 parts by mass of triphenylphosphine are premixed... The resin mixture was added dropwise and reacted at 85–90°C under reflux with stirring at 500 rpm for 4 hours to achieve siloxane grafting. The mixture was then refluxed at 75–80°C, and 6 parts of hydroxyethyl phosphate, 3.5 parts of diethanolamine, and 0.08 parts of hydroquinone were added sequentially. The mixture was stirred at 500 rpm for 4 hours to achieve phosphorus and nitrogen functionalization. The mixture was then cooled to below 40°C and filtered through a 150-mesh filter to obtain the siloxane-phosphorus-nitrogen modified bisphenol F-naphthol aldehyde hybrid resin.
[0037] The preparation of the methyl-Naphthol aldehyde resin includes the following steps: Naphthol: 37wt% formaldehyde aqueous solution: sodium hydroxide: deionized water = 110:60:4:25 by mass ratio; react at 40-50℃ and 400rpm for 40 minutes until the methyl-Naphthol is completely dissolved; heat to 65-75℃ and stir at 400rpm for 3 hours to carry out the hydroxymethyl addition reaction; continue heating to 85-90℃ and reflux at 400rpm for 2 hours; add dilute hydrochloric acid to adjust the pH of the system to 7.5; remove free water from the system under reduced pressure to obtain the methyl-Naphthol aldehyde resin with a molecular weight range of 800-1500.
[0038] The preparation method of the composite passivating agent includes the following steps: 60 parts by mass of aluminum borate, 50 parts by mass of sericite powder, 150 parts by mass of deionized water, and 1.2 parts by mass of sodium polyacrylate are added to a disperser and sheared at 1200 rpm for 50 min to obtain a suspension; the suspension is transferred to a jacketed reactor, and 6 parts by mass of cerium nitrate are added at 65℃ and stirred at 600 rpm for 50 min. The pH is adjusted to 9.0 with ammonia water to complete the rare earth ion adsorption; the temperature is lowered to 6℃, and 12 parts by mass of aniline are added. After stirring for 40 min, 30 parts of ammonium persulfate diluted with 130 parts of 1.2 mol / L hydrochloric acid aqueous solution were added dropwise at a rate of 2 drops / second. After the addition was completed, the mixture was stirred at 600 rpm for 8 h, with the temperature controlled between 2 and 6 °C throughout the process. The mixture was then filtered under pressure, and the filter cake was repeatedly washed with deionized water until the conductivity of the washing liquid was below 50 μS / cm. The mixture was then vacuum dried at 90 °C for 4 h, pre-oxidized at 420 °C in air for 1.5 h, calcined at 500 °C in nitrogen for 2 h, and pulverized to a median particle size of 1.8 μm to obtain the composite passivating agent.
[0039] The preparation method of the modified polyamide-ketoimine-epoxy composite includes the following steps: 120 parts by mass of dimer acid and 36 parts by mass of triethylenetetramine are added to a reaction vessel, a water separation and reflux device is installed, and the reaction is carried out at a temperature of 120-125℃ and 400 rpm for 1.5 h with stirring. The temperature is then increased to 200-220℃, and the mixture is dehydrated through a water separator for 5 h. The temperature is then lowered to 110-120℃, 22 parts by mass of methyl isobutyl ketone are added, and the mixture is refluxed for 4 h to complete the ketoimine end-capping. The temperature is then lowered to 80℃, 20 parts by mass of bisphenol F epoxy resin and 0.3 parts by mass of benzoic acid are added, and the mixture is reacted at a temperature of 90-95℃ and 400 rpm for 2.5 h. The temperature is then lowered to below 40℃, and the mixture is filtered through a 150-mesh filter to obtain the modified polyamide-ketoimine-epoxy composite.
[0040] The preparation method of the above-mentioned long-lasting heavy-duty anti-corrosion coating for industrial equipment includes the following steps: According to the formula, siloxane-phosphorus nitrogen modified bisphenol F-naphthol aldehyde hybrid resin and 1,4-butanediol diglycidyl ether are added to the paint mixing kettle and stirred at 600 rpm. Wetting agent, defoamer and dispersant are added in sequence and stirred for 15 min until uniform. The jacket is cooled and the temperature is controlled below 30℃. The composite passivating agent, hydrophobic silica and barium sulfate are added under stirring at 350 rpm and dispersed at high speed at 2000 rpm for 40 min. The mixture is then transferred to a sand mill and ground to a fineness of less than 20 μm under cooling water circulation and temperature control below 40℃. The mixture is then transferred back to the paint mixing kettle, anti-settling agent is added, and the mixture is stirred at 350 rpm for 30 min. The mixture is then filtered through a 150-mesh filter to obtain the base material component. When using, the base material component and curing agent component are mixed according to the formula ratio, and the mixture is adjusted to 5000 mPa·s (25℃) with 1,4-butanediol diglycidyl ether and allowed to stand to obtain the coating.
[0041] When using the coatings of the above embodiments, the viscosity is diluted to the application viscosity with 1,4-butanediol diglycidyl ether according to the painting method.
[0042] Comparative Example 1 The difference from Example 1 is that the mass ratio of the base material component to the curing agent component is changed to 100:17.
[0043] Comparative Example 2 The difference from Example 1 is that in the preparation of siloxane-phosphorus nitrogen modified bisphenol F-naphthol aldehyde hybrid resin, the step of "premixing 9 parts of γ-aminopropyltriethoxysilane and 0.12 parts of triphenylphosphine and then adding them dropwise into the resin mixture, stirring at 85-90°C and 400 rpm for 3.5 h under reflux to achieve siloxane grafting" is omitted.
[0044] Comparative Example 3 The difference from Example 1 is that in the preparation of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, the step of "temperature control at 75-80℃ for reflux and heat preservation, adding 5 parts of hydroxyethyl phosphate, 3 parts of diethanolamine, and 0.07 parts of hydroquinone in sequence; stirring at 400 rpm for 3.5 h to achieve phosphorus nitrogen functionalization" is omitted.
[0045] Comparative Example 4 The difference from Example 1 is that triphenylphosphine, diethanolamine, and hydroquinone are not added in the preparation of the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin.
[0046] Comparative Example 5 The difference from Example 1 is that the steps "pre-oxidation at 400°C for 1 hour in air atmosphere and calcination at 480°C for 1.5 hours in nitrogen atmosphere" are omitted in the preparation of the composite passivating agent.
[0047] Comparative Example 6 The difference from Example 1 is that the curing agent component is replaced with an equal amount of T31 epoxy resin curing agent.
[0048] The raw materials used in the above embodiments and comparative examples are as follows: 1,4-Butanediol diglycidyl ether is from Suzhou Senfida Chemical Co., Ltd., with a purity of 99%. The hydrophobic silica is from Hubei Huifu Nanomaterials Co., Ltd., HB-630, which is a hydrophobic fumed silica produced by treating hydrophilic fumed silica with hexamethyldisilazane (HMDS), and has a specific surface area of 270±30 m². 2 / g. Barium sulfate is from Hubei Xinrunde Chemical Co., Ltd., and passed through a 3000-mesh sieve. Bisphenol F epoxy resin is Nanya NPEF-170 epoxy resin, distributed by Guangzhou Xingtai Chemical Co., Ltd., with an epoxy equivalent of 170-180 g / eq. γ-aminopropyltriethoxysilane is from Nantong Zhonghe Chemical New Materials Co., Ltd., with a purity of 98%. Sericite powder is from Hubei Xinrunde Chemical Co., Ltd., and passed through a 1250-mesh sieve. Sodium polyacrylate is from Hunan Jianghai Environmental Protection Industry Co., Ltd., a general-purpose low molecular weight sodium polyacrylate dispersant, JH-09. Cerium nitrate is cerium nitrate hexahydrate, from Hubei Rishengchang New Materials Technology Co., Ltd., with a purity of 99%. BYK-333 is a BYK wetting and leveling agent. TEGO Wet 270 is a DIGIC wetting and leveling agent. BYK-065 is a BYK defoamer. TEGO Foamex N is a DIGIC defoamer. EFKA-6220 is an Efka dispersant. Solsperse 20000 is Lubrizol dispersant. KMT-4006 is KMT anti-settling agent. Aluminum borate passed through a 1250-mesh sieve. Hydroxyethyl phosphate is 2-hydroxyethyl methacrylate phosphate (HEMAP) with a purity of over 99%. The purity of the remaining raw materials is over 98%. The sources of the above raw materials are only examples and are not intended to limit the invention. T31 epoxy resin curing agent is from Jinan Jingsheng Chemical Co., Ltd. The main components of the curing agent include tertiary amines, imidazoles, amides, etc., and it is a commonly used epoxy resin curing agent on the market.
[0049] I. Preparation of test samples: 1. Substrate and Treatment: Unless otherwise specified, Q235 carbon steel plate with dimensions of 150mm×70mm×(1.5~2)mm is used. The substrate surface is sandblasted to remove rust, reaching Sa2.5 grade as specified in GB / T 8923.1, and the surface roughness is controlled within the range of 40μm~50μm.
[0050] 2. Panel Preparation and Curing: Except for the flexibility test, the dry film thickness of the coating was controlled at 80μm±5μm. The coating was cured for 7 days under standard conditions (23±2℃, relative humidity 50±5%) before testing. Three parallel samples were used for each performance test, and the results were taken as the arithmetic mean or common grade.
[0051] II. Testing Items and Methods: 1. Adhesion (Pull-off Method): Refer to GB / T 5210-2006; use an aluminum test column with a diameter of 20mm, and test at a constant tensile speed of 10mm / min until failure. Record the tensile force (MPa) at failure.
[0052] 2. Adhesion (cross-cut test): Refer to standard GB / T 9286-2021; the cross-cut spacing is 2mm, and special tape is used to peel off the coating. The coating peeling level is evaluated (level 0 to level 5).
[0053] 3. Pencil Hardness: Refer to GB / T 6739-2022; using a pencil of known hardness, with the pencil at a 45° angle to the painted surface, apply a load of 750g and advance at a speed of 1mm / s for at least 7mm. The highest pencil hardness without scratches is taken as the result.
[0054] 4. Impact resistance: Refer to GB / T 1732-2020; use a 1kg hammer to impact from a height of 50cm and observe whether the coating cracks or peels off. If it passes, gradually increase the height in 5cm increments until the coating is damaged, and record the maximum passing height (cm).
[0055] 5. Flexibility: Refer to GB / T 1731-2020; tinplate, dimensions conforming to standard requirements, dry film thickness of paint 30μm±3μm. The sample was bent 180° on shafts of different diameters, and the smallest shaft diameter (mm) at which the coating showed no cracks or peeling was recorded.
[0056] 6. Acid and alkali resistance: Refer to GB / T 9274-1988 (immersion method); immerse the samples in 5wt% H2SO4 aqueous solution and 10wt% NaOH aqueous solution respectively, at 23±2℃ for 720h. After cleaning, observe the paint film condition, rate it comprehensively according to GB / T 1766-2008, and then conduct a cross-cut adhesion test and record the rating.
[0057] 7. Oil resistance: Refer to GB / T 1734-1993 (immersion method); immerse in 30# machine oil at 23±2℃ for 7 days. After removal and cleaning, weigh immediately and calculate the coating weight change rate (%).
[0058] 8. Resistance to damp heat: Refer to GB / T 1740-2007; temperature 47±1℃, relative humidity 96±2%, continuous test for 2000h. After the test, observe the condition of the paint film and give a comprehensive rating according to GB / T 1766-2008.
[0059] 9. Artificial accelerated aging performance: Refer to GB / T 1865-2009 (Cycle A: Irradiation and Spraying); Xenon lamp aging chamber, 340nm irradiance 0.51W / m 2 The standard temperature for black paint was 65±3℃, and the relative humidity was 50~60%. The cycle was set as follows: 102 min of light exposure, followed by 18 min of spraying. The total test duration was 2000 h. After the test, the paint film condition was observed and rated according to GB / T 1766-2008.
[0060] 10. Resistance to high and low temperature alternation: One cycle consists of holding at -40±2℃ for 1 hour and at 80±2℃ for 1 hour, with a transition time not exceeding 1 minute. A total of 100 cycles are performed. Observe the paint film condition and rate it comprehensively according to GB / T 1766-2008.
[0061] Table 1 Test Results The coatings in Examples 1 to 3 construct a triple protection system of physical shielding, chemical passivation, and interface anchoring through the synergistic design of three major systems: substrate, passivation, and curing. Bisphenol F epoxy resin provides high crosslinking activity and substrate adhesion to the matrix. Naphthol aldehyde resin introduces rigid naphthalene rings to improve the coating's crosslinking density, heat resistance, and media barrier properties. Siloxane grafting introduces high-bond-energy Si-O-Si bonds, reducing the coating surface energy to achieve hydrophobic protection. Simultaneously, the Si-O bonds form chemical bonds with the metal substrate, upgrading the interface bonding from physical adsorption to chemical anchoring, thus strengthening the interface adhesion. Phosphorus and nitrogen functionalization is introduced through phosphate esters and diethanolamine, forming a dense phosphate passivation film on the metal surface to achieve chemical corrosion inhibition. This also increases the resin crosslinking points, improving the density of the shielding layer and blocking the penetration of corrosive media. The layered structure of aluminum borate and sericite powder forms a labyrinthine physical barrier in the coating, extending the penetration path of corrosive media. Rare earth ions in cerium nitrate form a stable cerium-based oxide passivation film on the metal surface, inhibiting cathodic oxygen reduction reaction. Polyaniline, after high-temperature pre-oxidation and calcination, forms a dense structure with redox reversibility, which helps the self-repair of local defects in the coating. The combination of these three components achieves a gradient synergistic protection of physical shielding, rare earth passivation, and organic corrosion inhibition. The curing agent combines the flexible segments of polyamide, the wet curing and low-temperature curing characteristics of ketimide, and the compatibility with epoxy resin, resulting in uniform cross-linking and avoiding defects such as internal stress, pinholes, and cracking, while improving wettability and adhesion to the substrate. The water-hydrolyzed primary amine property of ketimide preferentially consumes interfacial water molecules, reducing the risk of coating blistering, while forming an interpenetrating cross-linked network with the resin, improving the coating's resistance to media and structural stability. Hydrophobic silica enhances the coating's hardness and hydrophobic shielding properties, while barium sulfate, as an inert filler, strengthens the coating's density and mechanical strength. Specialized wetting, dispersing, defoaming, and anti-settling additives optimize the coating's workability, reduce defects such as pinholes, missed areas, and settling, and ensure overall coating uniformity, allowing the core protective system to perform at its best. 1,4-Butanediol diglycidyl ether is used as an active diluent, which both adjusts the application viscosity and participates in the crosslinking reaction.
[0062] In Comparative Example 1, the reduced amount of curing agent led to incomplete resin crosslinking, resulting in residual epoxy groups that formed polar defects in the coating. This reduced crosslinking density and created a loose, porous film structure, allowing corrosive media to easily penetrate. Uncrosslinked resin molecular chains exhibited high fluidity, weakening interfacial chemical bonds and causing decreased adhesion. The incomplete crosslinking network prevented effective stress transfer and dispersion, reducing mechanical properties. Furthermore, the insufficient density of the shielding layer caused all resistance to media, aging, and damp heat to deteriorate with increasing media penetration rates.
[0063] In Comparative Example 2, the absence of siloxane grafting severed the chemical anchoring pathway between the coating and the substrate, leaving interfacial bonding reliant solely on physical adsorption, resulting in a significant decrease in wet adhesion. The lack of a high-bond-energy Si-O-Si structure increased the coating's surface energy, reduced hydrophobicity, accelerated corrosive media penetration, and deteriorated acid and alkali resistance and resistance to damp heat. Furthermore, the absence of siloxane led to decreased resistance to heat-oxidative aging and UV degradation, a mismatch in thermal expansion coefficient with the substrate, and a susceptibility to internal stress cracking under alternating high and low temperatures, resulting in the failure of both physical shielding and interfacial protection.
[0064] In Comparative Example 3, the lack of phosphorus and nitrogen functionalization caused the resin to lose its chemical corrosion inhibition ability and fail to form a phosphate passivation film on the metal surface. Corrosive media easily diffused along the coating-substrate interface, resulting in deterioration of acid and alkali resistance. At the same time, the lack of phosphorus and nitrogen groups reduced the resin crosslinking points, decreased crosslinking density, and reduced shielding layer density, making it easier for media to penetrate into the substrate. The coating lacked active corrosion inhibition protection and was prone to blistering under humid and aging environments. Its resistance to humid heat and artificial accelerated aging decreased, retaining only some interfacial bonding and physical shielding effects provided by siloxane.
[0065] The absence of triphenylphosphine, diethanolamine, and hydroquinone in Comparative Example 4 resulted in a complete loss of control over resin synthesis, which is the core reason for the worst performance among all comparative examples. Triphenylphosphine, as an epoxy ring-opening catalyst, leads to incomplete siloxane grafting reactions and an uneven resin structure due to its absence. Diethanolamine, as a core component for phosphorus and nitrogen functionalization, completely negates its chemical corrosion inhibition and crosslinking enhancement effects due to its absence. Hydroquinone, as a polymerization inhibitor, causes oxidative degradation, molecular chain breakage, and even microgel formation during high-temperature reactions. The combined effect of these three factors results in extremely low resin crosslinking density, weak interfacial bonding, and easy oxidative degradation, leading to a significant decrease in all mechanical and protective properties of the coating.
[0066] In Comparative Example 5, the pre-oxidation and calcination steps of the composite passivator were omitted. High-temperature pre-oxidation and calcination are crucial for the formation of a stable structure in the composite passivator. Omitting these steps results in a loose core-shell structure, low crystallinity, and poor stability. Polyaniline failed to form a dense conjugated structure, losing its conductivity and self-healing ability, and easily swelled and detached in the medium. Rare earth cerium ions existed in a free state, readily dissolving rapidly and failing to achieve long-term slow-release passivation. The lamellar structure of aluminum borate and sericite powder was not activated, weakening the physical shielding effect. The compatibility between the passivator and resin decreased, forming interface defects in the coating, leading to reduced coating density and adhesion. All corrosion protection properties deteriorated with accelerated medium penetration.
[0067] In Comparative Example 6, the T31 curing agent showed poor structural compatibility with the modified resin of this invention, disrupting the synergistic effect between the curing system, resin, and substrate. T31 lacks a ketimide-free, moisture-curing structure, resulting in slow curing at low temperatures and high humidity, and a tendency to develop surface defects. It also lacks flexible polyamide segments, leading to a rigid and brittle cured network with significantly reduced impact resistance and flexibility. Interfacial bonding relies solely on physical adsorption, resulting in low adhesion and poor compatibility with the resin, easily causing microphase separation and insufficient coating density. Furthermore, T31 exhibits weak temperature and media resistance, readily degrading under alternating high and low temperatures, acid and alkali conditions, and humid environments, leading to rapid loss of protective performance.
Claims
1. A long-lasting, heavy-duty anti-corrosion coating for industrial equipment, characterized in that, The coating is prepared by mixing a base component and a curing agent component at a mass ratio of 100:26-28, and adjusting the pressure to 3000-5000 mPa·s with 1,4-butanediol diglycidyl ether. The base component is made from the following raw materials in parts by mass: 45-50 parts of siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin, 10-15 parts of composite passivating agent, 6-8 parts of hydrophobic silica, 9-13 parts of barium sulfate, 3-6 parts of 1,4-butanediol diglycidyl ether, 0.3-0.6 parts of wetting agent, 0.2-0.4 parts of defoamer, 0.4-0.8 parts of dispersant, and 0.3-0.7 parts of anti-settling agent. The curing agent component is a modified polyamide-ketoimine-epoxy composite.
2. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 1, characterized in that, The siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin is prepared by stirring bisphenol F epoxy resin and methyl naphthol aldehyde resin in propylene glycol methyl ether acetate, adding premixed γ-aminopropyltriethoxysilane and reacting with triphenylphosphine at 85-90℃, and then adding hydroxyethyl phosphate, diethanolamine and hydroquinone and reacting at 75-80℃. The composite passivating agent is prepared by stirring and dispersing aluminum borate, sericite powder, deionized water, and sodium polyacrylate, adding cerium nitrate at 60-65℃ and dispersing, adjusting the pH to 8.5-9.0, adding aniline at 2-6℃ and stirring, then adding diluted ammonium persulfate in hydrochloric acid solution to react, followed by pressure filtration, washing, drying, pre-oxidation at 380-420℃, calcination at 450-500℃, and pulverization. The modified polyamide-ketoimine-epoxy composite is prepared by reacting a dimer acid with triethylenetetramine at 120–125°C, dehydrating it at 200–220°C, adding methyl isobutyl ketone for reflux dehydration at 110–120°C, adding bisphenol F epoxy resin and benzoic acid at 70–80°C, and reacting at 90–95°C.
3. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 1, characterized in that, The wetting agent is BYK-333 or TEGO Wet 270; the defoamer is BYK-065 or TEGO Foamex N; the dispersant is EFKA-6220 or Solsperse 20000; and the anti-settling agent is KMT-4006.
4. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 1, characterized in that, The siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin is prepared by mixing bisphenol F epoxy resin, methyl naphthol aldehyde resin, propylene glycol methyl ether acetate, γ-aminopropyltriethoxysilane, triphenylphosphine, hydroxyethyl phosphate, diethanolamine, and hydroquinone in a mass ratio of (60-70):(30-40):(25-30):(8-10):(0.1-0.15):(4-6):(2.5-3.5):(0.05-0.08). The bisphenol F epoxy resin and methyl naphthol aldehyde resin are stirred in propylene glycol methyl ether acetate at 70-75°C. Premixed γ-aminopropyltriethoxysilane and triphenylphosphine are added and reacted at 85-90°C. Hydroxyethyl phosphate, diethanolamine, and hydroquinone are added and reacted at 75-80°C.
5. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 4, characterized in that, The preparation method of the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin includes the following steps: 60-70 parts by weight of bisphenol F epoxy resin, 30-40 parts by weight of methyl naphthol aldehyde resin, and 25-30 parts by weight of propylene glycol methyl ether acetate are stirred at 70-75°C for 30-50 min to obtain a resin mixture; 8-10 parts by weight of γ-aminopropyltriethoxysilane and 0.1-0.15 parts by weight of triphenylphosphine are premixed and added dropwise to the resin mixture, and the mixture is stirred at 85-90°C for 3-4 h; 4-6 parts by weight of hydroxyethyl phosphate, 2.5-3.5 parts by weight of diethanolamine, and 0.05-0.08 parts by weight of hydroquinone are added at 75-80°C, and the mixture is stirred for 3-4 h; the mixture is then filtered to obtain the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin.
6. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 1, characterized in that, The composite passivating agent is composed of aluminum borate, sericite powder, deionized water, sodium polyacrylate, cerium nitrate, aniline, 1.0–1.2 mol / L hydrochloric acid aqueous solution, and ammonium persulfate in a mass ratio of (50–60):(40–50):(120–150):(0.8–1.2):(4–6):(8–12):(120–130):(20–30). Aluminum borate, sericite powder, deionized water, and sodium polyacrylate are stirred and dispersed. Cerium nitrate is added at 60–65°C and dispersed, and the pH is adjusted to 8.5–9.
0. Aniline is added and stirred while maintaining the temperature at 2–6°C. Diluted ammonium persulfate in 1.0–1.2 mol / L hydrochloric acid aqueous solution is added dropwise. The mixture is stirred and reacted for 6–8 hours. After pressure filtration, washing, and drying, it is pre-oxidized in air at 380–420°C, calcined in nitrogen at 450–500°C for 1.5–2 hours, and then pulverized to obtain the final product.
7. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 6, characterized in that, The preparation method of the composite passivating agent includes the following steps: 50-60 parts by weight of aluminum borate, 40-50 parts by weight of sericite powder, 120-150 parts by weight of deionized water, and 0.8-1.2 parts by weight of sodium polyacrylate are stirred and dispersed to obtain a suspension; 4-6 parts by weight of cerium nitrate are added at 60-65℃, stirred and dispersed, the pH value is adjusted to 8.5-9.0, and at a temperature of 2-6℃, 8-12 parts by weight of aniline are added and stirred; 20-30 parts by weight of ammonium persulfate diluted with 120-130 parts by weight of 1.0-1.2 mol / L hydrochloric acid aqueous solution are added dropwise, stirred for 6-8 hours, filtered under pressure, the filter cake is washed with deionized water until the conductivity of the washing liquid is below 50 μS / cm, vacuum dried, pre-oxidized at 380-420℃ in air for 1-1.5 hours, calcined at 450-500℃ in nitrogen for 1.5-2 hours, and pulverized to a median particle size of below 3 μm to obtain the composite passivating agent.
8. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 1, characterized in that, The modified polyamide-ketoimine-epoxy composite is prepared by reacting dimer acid, triethylenetetramine, methyl isobutyl ketone, bisphenol F epoxy resin, and benzoic acid in a mass ratio of (100-120):(32-36):(18-22):(15-20):(0.2-0.3). The dimer acid is first reacted with triethylenetetramine at 120-125°C for 1-1.5 h, then dehydrated at 200-220°C for 4-5 h, then methyl isobutyl ketone is added at 110-120°C and refluxed for 3-4 h, and finally bisphenol F epoxy resin and benzoic acid are added at 70-80°C and reacted at 90-95°C for 2-2.5 h.
9. The long-lasting heavy-duty anti-corrosion coating for industrial equipment according to claim 8, characterized in that, The preparation method of the modified polyamide-ketoimine-epoxy composite includes the following steps: 100-120 parts by weight of dimer acid and 32-36 parts by weight of triethylenetetramine are stirred and reacted at 120-125°C for 1-1.5 hours; dehydrated at 200-220°C through a water separator for 4-5 hours; 18-22 parts by weight of methyl isobutyl ketone are added at 110-120°C and refluxed for 3-4 hours; 15-20 parts by weight of bisphenol F epoxy resin and 0.2-0.3 parts by weight of benzoic acid are added at 70-80°C; the mixture is reacted at 90-95°C for 2-2.5 hours; and filtered to obtain the modified polyamide-ketoimine-epoxy composite.
10. The method for preparing a long-lasting, heavy-duty anti-corrosion coating for industrial equipment as described in claim 1, characterized in that, The process includes the following steps: According to the formula, stir the siloxane-phosphorus nitrogen-modified bisphenol F-naphthol aldehyde hybrid resin and 1,4-butanediol diglycidyl ether, and then add wetting agent, defoamer, and dispersant in sequence while stirring; add composite passivating agent, hydrophobic silica, and barium sulfate at temperatures below 30°C and disperse them, then grind them to a fineness of less than 20 μm at temperatures below 40°C; add anti-settling agent and stir, then filter to obtain the base material component; when using, mix the base material component and curing agent component according to the formula ratio, adjust the pressure to 3000-5000 mPa·s with 1,4-butanediol diglycidyl ether, and let it stand to obtain the coating.